1. Field of the Invention
The present invention relates to a system for positioning and transferring tubes, and more particularly to a method and apparatus for orienting for further processing unended multiwall paper tubes from which shipping sacks are formed.
According to the system, unended tubes formed in a tuber are stacked into hands and delivered lengthwise to a position adjacent the entry section of bottomer or ender equipment which receives the hands sidewise and closes and seals one end of each tube. Since customer requirements vary, some requiring the tubes to be ended flap-to-face at one end or at the opposite end, or flap-to-back at one end or at the opposite end, the tubes must be oriented for proper entry into an ender based upon those requirements. Thus, the present system contemplates positioning the tubes for entry into the ender in one of four dispositions, that is, with one side or the other (the topside or the bottom side) facing upwardly and, in either case, with one end or the other facing a given direction relative to the ender.
Since a tuber may produce tubes at a rate of the order of 210 per minute and an ender can end tubes at a rate of the order of 75 per minute, the system includes at least one and preferably two enders and a by-pass to provide optimum utilization of the enders. For example, if two enders are used and the first ender for any reason cannot accept tubes due to a backup or jam, the tubes are automatically transported to the second ender during normal production. If the second ender cannot accept tubes, excess tubes are fed automatically to the by-pass which feeds the excess tubes back to the enders when both are again in operation and no new tubes are being supplied by the tuber due, for example, to tuber failure or normal down time for a print roll change. Thus, the by-pass supplies excess tubes to the enders so that the enders remain in production while the tuber is down.
2. Description of the Prior Art
As flat lengths of paper move through a tuber to be formed into tubes, the surface of the inner layer is lubricated by moistening it with a spray of water to reduce friction between the paper and metal guides that fold the paper to form the tubes. Additionally, the lengthwise seam formed by the tuber is adhered with a water base adhesive and the several layers are spot glued together along the tube ends to prevent slippage of the individual layers relative to one another. In the past, the moisture from the spray and the adhesive was absorbed into the paper before the tubes could be bottomed or ended in the enders, because tubes were not delivered directly from the tuber to an ender and, in any case, any required reorientation of the tube hands was done manually. Such absorption often caused problems in the ending operation because the hot melt adhesive used to end the tubes would not adhere to paper in which moisture had been absorbed. Accordingly, the tubes had to be stored for a period of from 24 to 48 hours in a controlled atmosphere, or up to three days in an uncontrolled atmosphere to allow complete drying.
There is available a machine that inverts a hand of tubes about the longitudinal axis of the tubes but is unable to reverse the tubes end to end. This device is part of a flow through system from tuber to ender so that if any part of the system fails, the entire system must be taken out of production.